Interaction between Acidic Phospholipids Found in Bacterial Membranes and DnaA Protein, the Initiator of Escherichia coli Chromosomal Replication

• J Sandberg

  English

  Author

Phospholipids that are anionic, or acidic, including cardiolipin (CL) and phosphotidylglycerol
(PG), are involved in a number of cellular processes. Here we summarize interesting in vitro and in vivo
data that point to emerging roles for acidic phospholipids in controlling the commencement of
Escherichia coli chromosome replication mediated by the DnaA protein. Although both PG and CL may
prevent the DnaA protein from binding DNA, in vitro acidic phospholipids in a fluid bilayer facilitate the
transformation of inactive ADP-DnaA into replicatively competent ATP-DnaA. We go over how cellular
acidic phospholipids may affect the DnaA protein's initiation activity both favorably and unfavorably,
ensuring that chromosomal replication happens only once per cell cycle. Numerous studies have
connected membrane curvature with the subcellular distribution of different integral and peripheral
membrane proteins, and fluorescence microscopy has shown that PG and CL occur in domains at the cell
poles and mid-cell. The DNA of E. coli is located at the cell membrane and forms helical formations
along the cell's longitudinal axis. We suggest that the bacterial membrane's acidic phospholipids and the
DnaA protein interact to assist regulate the temporal and spatial regulation of chromosomal replication.

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